Step by Step Procedure to create a WCF Service Application for SharePoint 2013 using Visual Studio 2012

Below article explains you how to make a REST call to a custom WCF service from a SharePoint 2013 Provider Hosted Application. 

http://www.sharepointpals.com/post/Step-by-Step-Procedures-to-create-a-WCF-Service-Application-for-SharePoint-2013